Trump 'not considering' firing Mueller

US President Donald Trump says he is not considering firing special counsel Robert Mueller even as his administration is again forced to grapple with the growing Russia probe that has shadowed the White House for much of his initial year in office.

Trump returned to the White House from Camp David and was asked if he would consider triggering the process to dismiss Mueller, who is investigating whether the president's Republican campaign coordinated with Russian officials during last year's election.

But he did add to the growing conservative criticism of Mueller's move to gain access to thousands of emails sent and received by Trump officials before the start of his administration, yielding attacks from transition lawyers and renewing chatter that Trump may act to end the investigation.

"It's not looking good. It's quite sad to see that, my people were very upset about it," Trump said. "I can't imagine there's anything on them, frankly. Because, as we said, there's no collusion. There's no collusion whatsoever."

On Saturday, the general counsel for the transition group sent a letter to two congressional committees arguing Mueller's investigators had improperly obtained thousands of transition records.

The investigators did not directly request the records from Trump's still-existing transition group, Trump for America, and instead obtained them from the General Services Administration, a separate federal agency that stored the material, according to those familiar with the Trump transition organisation.

A spokesman for Mueller said the records were obtained appropriately.

But many Trump allies used the email issue as another cudgel with which to bash the probe's credibility. Members of the conservative media and some congressional Republicans have begun to systematically question Mueller's motives and credibility while the president himself called it a "disgrace" that some texts and emails from two FBI agents contained anti-Trump rhetoric. One of those agents was on Mueller's team and has been removed.